Precision positioning techniques required in carrying out a micromachining or a micro-displacement operation has come to be ranked to take a very important position, and are sought to be higher in precision than ever.
Making good use of micromachining technologies for manufacturing a positioning device allows its bulk production in a batch process, and has an advantage of eliminating the need to assemble each device product individually while yielding products small-sized, at a low cost and with a reduced individual difference. For this reason, recent years have seen extensive researches conducted on various microactuators and microsystems for positioning (see M. Steven Rodger et al, “Intricate Mechanisms-on-a-chip Enabled by 5-Level Surface Micro Machining”, Digest of Transducers '99, Sendai, Japan, June 1999, pp. 990–993). Faced with the problem of importance that the force produced is unsatisfactory and that the movable distance is insufficient, however, micro-actuators so far proposed have had a limited extent of their applicability. For example, an impact driving mechanism using a piezoelectric element has been proposed (see Toshiro Higuchi, Masahiro Watanabe, Ken-ichi Watanabe, “Ultra-precision Positioning Mechanism utilizing Rapid Deformation of a Piezoelectric Element”, Journal of the Society of Precision Engineering, 54-11, 2107 (1998), which using a frictional force and an piezoelectric element, has both a very small displacement in a nanometer range and a movable distance utmost minimum in principle, but needs to be built up individually and has a limitation in miniaturization.
Further, microactuators so far proposed are poor in reliability measure such as to prevent entry of dust and moisture in air and are thus inferior in environmental reliability.
It is accordingly a first object of the present invention to provide a microactuator that eliminates the need to assemble individually and can be miniaturized much more than ever and, in particular, to provide a self-moved impact driven actuator which with an electrostatically driven, movable mass member in its driving source is high in environmental reliability. It is a second object of the present invention to provide a method of making such a microactuator utilizing a bulk micromachining technique.